Hello all,
I have asked in the #trac irc channel and got some information on this which is below.
Trac people pointed me to
http://trac.edgewall.org/wiki/SpamFilter for spam registration but I thought someone already installed and enabled this. A good way to check this out is in spam filter monitoring within the plugin for trac.
I have asked Chris (paroneayea) and Simon (simonft) who have given various answers but would be good if people can start to register on Trac again.
If there is more information, I need to find please let me know.
Amelia Rose (First Name)